Method of making a heat exchanger



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May 11, 1965 v PL oDDY 3,182,380

METHOD 0F MAKING A HEAT EXCHANGER 2 Sheets-Sheet 1 Original Filed Aug. 14. 1956 May 11, 1965 i E. P. ODDY 3,182,380

' METHOD oF MAKING A HEAT EXCHANGER Original Filed Aug. 14, 1956 2 Sheets-Sheet 2 3 f fnvenzlbrf l 'Ida/aref?? Od@ United States Patent O 3,182,380 METHOD F MAKING A HEAT EXCHANGER Edward I. Oddy, Detroit, Mich., assigner to Borg-Warner Corporation, Chicago, Ill., a corporation of Illinois Original application Aug. 14, 1956, Ser. No. 603,950. Divided and this application .lune 25, 1962, Ser. No.

8 Claims. (Cl. 29-157.3)

The present invention relates to heat exchangers, and more particularly to heat exchangers of the type comprising tube sheets which integrally form a plurality of tubes joined at their opposite end portions to integral tanks, the tubes being separated by portions having tins or louvers provided therein, the devices incorporating the present invention having particular suitability as automobile-or other vehicle-radiators.

Briefly described, the present invention relates to a method of forming a heat exchanger from a tube sheet. The heat exchanger is characterized as having a plurality of spaced apart elongated tubes with transversely disposed ins formed integral therewith. The configuration of the tubes and fins is such that the heat exchange media may be passed through the heat exchanger in a direction transverse the original plane of the tube sheet.

Other objects and features of the invention will be readily apparent to those skilled in the art from the speciiication and appended drawings illustrating certain preferred embodiments in which:

FIGURE 1 is a front elevational view of a device constructed in accordance with the present invention;

FIGURE 2 is a side elevational view of the device in FIGURE l;

FIGURE 3 is a sectional view along the plane of line 3 3 of FIGURE 1;

FIGURE 4 is an enlarged sectional view along the plane of line 4--4 of FIGURE l;

FIGURE 5 is an enlarged perspective View of a portion of the device illustrated in FIGURE 1;

FIGURE 6 is a view similar to FIGURE 3 illustrating a modification of the device illustrated in FIGURE l;

FIGURE 7 is an enlarged sectional view along the plane of line 7-7 of FIGURE 5;

FIGURE 8 is a modification of the device illustrated in FIGURE 1;

FIGURE 9 is an enlarged sectional View along the plane of line 9-9 of FIGURE 8.

With reference to the figures, which are more or less schematic, and with particular reference to FIGURE 1 there is disclosed therein means delining an integral fluid circuit which comprises a tube sheet 1 of aluminum or other suitable heat conducting and fluid impervious material. Such tube sheets may be either of the type manufactured by Reynolds Metal Co. or others known as material manufactured by the Roll-Bond process; or other similar constructions. The product marketed by Reynolds Metal Co., manufactured under the Roll-Bond process is described in the February 1956 issue of the magazine Modern Metals and also in the November 1954 issue of Modern Metals. In using the term tube sheet herein reference is made to such types of structure or any other comparable or similar structure, which comprises an integral combination of tubing and tube spacing sheet formed from a plurality of sheets oi metal integrally bonded together except in areas forming the fluid circuit. The tube sheet 1 comprises integrally an upper, fluid carrying tank portion Z and a plurality of spaced tubes 3 in duid communication at one end with the tank portion 2. The tubes 3 are initially separated by relative- 1y ilat, thin, non-fluid carrying portions 4 integral with the tubes 3. In uid communication with the opposite "ice ends of each of the tubes 3 is a lower, fluid carrying tank portion S also integrally formed as part of tube sheet 1. The upper tank portion 2 may be connected by a suitable luid tight bond, such as soldering, to a manifold 6; the lower tank 5 may be similarly connected to a lower manifold '7.

It should be noted, therefore, that the elements 2 through 5 are integrally formed from a single tube sheet which comprises a pair of sheets of material intimately joined together except in the areas forming the tanks 2 and 5 and the tubes 3. Each of the liat portions 4 between and adjacent the tubes 3 has been sheared or slit, and from each such ilat portion 4 has been formed by twisting a plurality of louvers or tins ti disposed at an angle to portions 4; it will be seen that openings in portions 4 are formed thereby.

As illustrated in FIGURE 5, each of the tubes 3 is formed such as by expanding the tube pattern in a manner as taught in the aforesaid Modern Metals magazine such that the tube is relatively thin laterally (in a direction measured parallel to the original plane of the tube sheet) and is relatively deep axially (in a direction measured transverse to the original plane of the tube sheet) so that the major axial dimension transverse the plane of the tube sheet of each tube is several times its minor dimensions parallel to the plane of the tube sheet; this permits the tins 8 to have, as ilrustrated in FIGURE 5, a relatively substantial dimension transverse the plane of the tube sheet.

As previosuly described, the flat areas 4 between the tubes 3 are integral with the tubes 3. As best illustrated in FIGURE 7, when the iiat portions 4 are sheared or slitted, as previously explained, and the iins 8 are twisted out of the plane of portions @l openings are formed in portions A; of area substantially equal to the area of the tins to permit the flow of air or other iluid in a direction perpendicular to the plane of the tube sheet l. The resultant connection between each side of each lin 8 and the adjacent portion of the fiat area 4 is substantially in the form illustrated in the enlarged view of FIGURE 7. In this figure, the sheared portion is lrepresented by the length indicated as a; as the ins S are ltwisted there is a tendency for the material to 4tear partly within the area b; at the same time, the material in this area is slightly distorted as illustrated. There remains a tie of material between the iins 8 and the adjacent section of the flat portion 4 approximately of the section shown at c in FIGURE 7. It will be obvious to those skilled in the art that this section of material will transfer heat from the adjacent tube 3 an-d flat portion 4 to the iin 8.

It will be seen from the foregoing description that when the device is used, for example, as an automobile radiator iiuid may pass from the vehicles engine to the upper manifold e, or other comparable fitting, through the upper tank 2, the tubes 3, the lower tank S and into the lower manifold or other suitable fitting 7, from which it would be recirculated through the engine. This fluid will be cooled as it passes through tubes 3 by virtue of air flow along the surface of tubes S-the primary cooling surfaces-and over the surfaces of iins ti-secondary cooling surfaces. As illustrated in FIGURE 2, when the device of the present invention is utilized as an automobile radiator it is preferable to employ a plurality of axially spaced tube sheets 1 of the general type previously described. As illustra-ted in FIGURE 3, all of the tins 8 and tubes 3 may be axially aligned, or as illustrated in FIG- URE 6 the tubes 3 and tins 8 may be staggered to produce air turbulence as it liows through the radiator. It should also be noted, as also illustrated in FIGURE 2, that the fins in the plurality or axially spaced tube sheets may either be horizontal or may be at an angle to the horizontal to sa produce a serpentine air i'low through the radiator. It will be obvious to those skilled in the art that the integral, intimate bond between the tubes 3 and tins 8 will etfect a substantially/.improved degree of thermal conductivity therebetween which will make the device of the present invention a singularly ecient heat exchanger and one which is simply and readily produced.

Considering how the modiication illustrated in FIG- URES 8 and 9, it should be understood that the particular modification illustrated therein is identical with respect to the elements previously described with the exception of the formation of the tins and their attachment to the remainder of the structure. In the embodiment illustrated in FIGURES 8 and 9, the thin portions d between the tubes 3 are initially provided with a plurality of vertically spaced, narrow, pierced slots, (shown in the upper part of FIGURE 8) the flat material between the slots then being twisted to form iins S which are angularly disposed with respect to portions 4 and preferably of the width from 1/s inch to 1A inch (as shown in the lower part of FIGURE 8 and FIGURE 9). By forming the iins 8' inthis manner there is no appreciable reduction in the cross section of material through which the heat must ow from the tube to the tins; in other words the area of the material joining each tube and the adjacent lin is substantially equal in cross section to the amount of cross section of material which exists in the lin 8' itself.

It will readily appear to those skilled in the art that the device of the present invention is a substantial improve# ment over heat exchangers previously known in that there are-with the exception of the connection of the tube sheets to the upper and lower manifoldsno soldered or brazed joints whatsoever so that the manufacturing process is significantly simplified and the possibility of leaks substantially eliminated. In addition, the necessity for effecting the proper bond between the secondary sur,- faces, comprising thev fins, in radiators of the prior art is obviated and in the present invention there is no chance whatsoever of an improper bond or thermal contact between the tins and the tubes inasmuch as the connection between these elements is an integral one. Not only is this a signicant factor from a manufacturing standpoint, but it ensures a desirable product throughout the length of utilization of the device inasmuch as the bond between the secondary and primary surfaces of the structure cannot be less than initially contemplated because of errors in the manufacturing process, vibration or'aging. In addition, higher internal fluid pressures are possible than with any of the heat exchangers previously employed, so that the size of the heat exchanger itself may be signicantly reduced with a consequent substantial saving in cost and weight.

As a specic example, for illustrative purposes only and not as a limitation, of the manner in which the tube sheets described herein may be fabricated, the teachings of United States Letters Patent No. 2,690,002 issued Septomber 28, 1954 to Leland H. Grenell may be employed.

This application is a division of an application tiled August 14, 1956, Serial No. 603,950 entitled Heat yExchanger While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention istto be given its broadest possible interpretation within the terms of the following claims.'

I claim:

l. A method for making a heat exchanger of the tube sheet type comprising the steps of integrally bonding two sheets of metal each to the other to form a tube sheet having a plurality of spaced apart unbonded zones, expanding said unbonded zones to form a plurality of tubes with intermediate ilat portions extending between said tubes, transversely slitting said flat portion between Said 4 tubes to form a series of tins extending between said tubes with end portions of said fins being such that said flat portion adjacent said tubes is not severed from said tubes, bending said fins to provide a iin vstructure extending transverse to the plane of the tube sheet with one edge' of the iin disposed on one side of the tube sheet and the other edge of the iin disposed on the opposite side of the tube sheet.

2. A method for making a heat exchanger of the tube sheet type comprising the steps of integrally bonding two sheets of metal each to the other to form a tube sheet having a plurality of spaced apart unbonded zones, expanding said'unbonded zones to form a plurality of tubes with intermediate flat portions extending between said tubes, transversely slitting said at portion between said tubes to form a series of ns intermediate said slits, bending said fins in a manner such that the iin material intermediate the ends of the slits is twisted to provide a n structure .extending transverse to the plane of the tube sheet with one edge of theriin Vdisposed on one side of the tube sheet and the other edge of the fm disposed on the opposite side of the tube sheet and such that the ends of said ns remain integral with said tubes.

3. A method for making a heat exchanger of the tube sheet type comprising the steps ofintegrally bonding two sheets of metal each to the other to form a tube sheet having a plurality o-fspaced apart unbonded zones, expanding said unbonded zones to form a plurality of tubes with intermediate at portions extending between said tubes, transversely slitting said flat portion between said tubes to form a series of ns intermediate said slits, bending said fins to provide a iin structure extending transverse to the plane of the tube sheet with one edge ofthe iin disposed on one siderof the tube sheet and the other edge of the lin disposed on the opposite side of the tube sheet and the middle of the iin disposed in the plane ofthe tube sheet and with the end of each of said tins being integral with said tubes and being integral with the engl of the adjacent iin throughout'the entire length of said tu e.

4. A method for making a heat exchanger of the tube sheet type wherein the flow of heat exchange media is transverse the plane of said tube sheet comprising the steps of integrally bonding two sheets of metal each to the other-to form a tube sheet having a plurality of spaced apart unbonded zones; expanding said unbonded zones to form aY plurality of tubes each having a length dimension, a lateral dimension being in the plane of the tube sheet, and an axial dimension in excess of said lateral dimension, said axial dimension being transverse to the plane of the tube sheet, and to form intermediate dat portions extending between said tubes; transversely slitting said rflat portion between said tubes to form a series lof iins intermediate said slits; bending said tins to provide a iin structure extending transverse tothe plane of the tube sheet with one edge of the iin disposed on one side of the tube sheet and the other edge of the lin disposed on the opposite side of the tube sheet.

5. A method for making a heat exchanger of the tube sheet type comprising the steps of integrally bonding two sheets of metal each to the other to forma tube sheet having a plurality of spaced apart unbonded zones, expanding said unbonded zones to form a vplurality of tubes with intermediate flat portions extending between said tubes, transversely slitting said flat portion between said tubes to form a series of iins extending between said tubes with end portions of said tins remaining integral with said tubes and integral with the end portion of the adjacent iin, bending'said iins to provide an opening encompassing the major portion of said at portion and to provide a iin structure extending transverse to the plane of the tube sheet with one edge of the lin disposed on one side of the tube sheet and the other edge of the iin disposed on the opposite side of the tube sheet and with the area of said iin being substantially equal to the area defined by said opening.

6. A method for making a heat exchanger of the tube sheet type wherein the ow of heat exchanger media is transverse the plane of said tube sheet comprising the steps of integrally bonding two sheets of metal each to the other to form a tube sheet having a plurality of spaced apart unbonded zones, expanding said unbonded zones to form a plurality of tubes having a lateral dimension in the plane of said tube sheet and an axial dimension transverse to the plane of the tube sheet which axial dimension is greater than said lateral dimension with unexpanded intermediate flat portions extending between said tubes, transversely slitting said at portion between said tubes to form a series of iins intermediate said slits, bending said tins in a manner such that the fin material intermediate the ends of the slits is twisted to provide a fin structure extending transverse to the plane of the tube sheet with one edge of the iin disposed on one side of the tube sheet and the other edge of the n disposed on the opposite side of the tube sheet.

7. A method for making a heat exchanger of the tube sheet type comprising the steps of integrally bonding two sheets of metal each to the other to form a tube sheet having a plurality of spaced apart unbonded zones, expanding said unbonded zones to form a plurality of tubes with intermediate flat portions extending between said tubes, transversely slitting said at portion between said tubes to form a series of ns extending between said tubes with end portions of said fins remaining integral with said tubes and integral with the end portion of the adjacent n, bending said tins to provide a iin structure extending transverse to the plane of the tube sheet and to provide an opening encompassing the major portion of said fiat portion, said tins having one edge on one side of the tube sheet and another edge disposed on the opposite side of the tube sheet and the middle thereof disposed in the plane of the tube sheet.

8. A method for making a heat exchanger of the tube sheet type wherein the flow of heat exchanger media is substantially perpendicular to the plane of said tube sheet comprising the steps of integrally bonding two sheets of metal each to the other to form a tube sheet having a plurality of spaced apart unbonded zones; expanding said unbonded zones to form a plurality of tubes each having a length dimension, a lateral dimension being in the plane of the tube sheet, and an axial dimension in excess of said lateral dimension, said axial dimension being transverse to the plane of the tube sheet, and to form intermediate hat portions extending between said tubes; transversely slitting said flat portion between said tubes to form a series of ns intermdiate said slits; bending said fins to provide a n structure extending transverse to the plane of the tube sheet with one edge of the fin disposed on one side of the tube sheet and the other edge of the fin disposed on the opposite side of the tube sheet and to provide an opening through said tube sheet encompassing substantially all of said flat portion, said opening being .suitable for the passage of a heat transfer media at substantially right angle to said plane of the tube sheet and substantially parallel to said axial dimension of said tubes.

References Cited by the Examiner UNITED STATES PATENTS 2,175,394 #l0/39 Hewell 165-148 2,286,271 6/42 Higham 16S-149 2,703,701 3/55 Simpelaar 113-118 2,759,247 8/56 Grenell et al 29-157 .3 2,856,162 10/58 Adams 29-157.3 2,924,437 2/60 Wilkins 29`1573 3,104,701 9/63 Jacoby 29-157.3

FOREIGN PATENTS 109,538 1/40 Australia.

WHITMORE A. WILTZ, Primary Examiner. 

1. A METHOD FOR MAKING A HEAT EXCHANGER OF THE TUBE SHEET TYPE COMPRISING THE STEPS OF INTEGRALLY BONDING TWO SHEETS OF METAL EACH OF THE OTHER FORM A TUBE SHEET HAVING A PLURALITY OF SPACED APART UNBOUNDED ZONES, EXPANDING SAID UNBONDED ZONES TO FORM A PLURALITY OF TUBES WITH INTERMEDIATE FLAT PORTIONS EXTENDING BETWEEN SAID TUBES, TRANSVERSELY SLITTING AND FLAT PORTION BETWEEN SAID TUBES TO FORM A SERIES OF FINS EXTENDING BETWEEN SAID TUBES WITH END PORTIONS OF SAID FINS BEING SUCH THAT SAID FLAT PORTION ADJACENT SAID TUBES IS NOT SERVED FROM SAID TUBES, BENDING SAID FINS TO PROVIDE A FIN STRUCTURE EXTENDING TRANSVERSE TO THE PLANE OF THE TUBE SHEET WITH ONE EDGE OF THE FIN DISPOSED ON ONE SIDE OF THE TUBE SHEET AND THE OTHER EDGE OF THE FIN DISPOSED ON THE OPPOSITE SIDE OF THE TUBE SHEET. 